In order to select songs to play in the form of a playlist, this task can be accomplished through the OLED screen. Because the display screen uses the I2C interface, it can effectively save IO port resources. In addition, the display screen is wider than the usual OLED, and it is also easy to display the song name.

5.OLED screen display and menu selection

1) Complete the definition macros for 3 constant lights

2) Add relevant display functions

3) Complete the program flow modification as shown in Figure 23, and then regenerate the code. Due to the limitations of the compiler, the development process with EasyCode Magic Box has been completed. Later we will use KEIL to complete the subsequent processing.

Figure 23 Program flow

4) Use Keil to open the generated project file, and then modify the compilation mode according to Figure 24.

5) Reference the font header file in the program header

#include"codetab.h"

Figure 24 Modify the Keil compilation mode

5) Modify the main program content as shown in Figure 25, and then recompile. The compilation result is shown in Figure 26.

Figure 25 Main program content

Figure 26 Compilation results

6. Overall functional verification

When the OLED screen, MP3 player module and soft keys are connected, pressing K4, K1, K2, and K3 in sequence can realize song selection, play, stop and volume adjustment. The effects are shown in Figures 27 to 31.

Figure 27 Power-on effect